Automatic stabilizer for aeroplanes



Nov'. 27 1923.

H. A. PETRIE AUTOMATIC STABILIZER FOR AERoPLANEs Filed July 22. 1921 7sheets-sheet 1 ATTORNEY WITNESSES 1,475,869 H. A. PETRIE AUTOMAT I C STABILI Z ER FOR AEROPLANES Nov. 27 1923 Filed July 22. 1921 7Sheets-Sheet 2 WITNESSE" A'fTORNEY Nov. 27, 1923` 1,475,869

H. A. PETRIE AUTOMATIC STABILIZER FOR AEROPLANES Filed July 22. 1921 7Sheets-Sheet 5 @qui v/fa, BY W. j

Nov. 27 1923A H. A. PETRIE AUTOMATIiC STABILIZER FOR AEROPLANES '7Sheets-Sheet 4 Filed July 22. 1921 ATTORNEY WITNESSES:

Nov. 27, 1923 1,475,869

H. A. PETRIE AUTOMATIC STABILIZER FOR AEROPLANES Filed July 22. 1921 '7Sheets-Sheet 5 INVENTOR WITNESSES,l ATTORNEY Nov. .27',` 1923 1,475,869H. A. PETRIE Y AUTOMATIC STABILIZER FOR AEROPLANES Filed July 22. 1921 7Sheets-Sheet 6 ATTORN EY wl'rNEsssS:

Nov. 27',4 1923 H. A. PETRIE.

AUTOMATIC STABILIZER FOR AEROPLANES Filed July 22, 1921 7 Sheets-Sheet'7 INVENTOR ATTO R N EY WlTN ESSES:

Patented Nov. 27, 1923.

HARRY A. PETRIE,

0F HARRISBURG; PENNSYLVANIA.;

y AUTOMATIC STABILIZER FOB-AEROPLANES.

Application led July 22, 1921. Serial No. 486,753'.

To all whom it may concern Be it known that I, HARRY A.' PETRIE, acitizen of Harrisburg, residing at 1341 Vernon St., Harrisburg, in thecounty of Dauphin and State of Pennsylvania, have invented new anduseful Improvements in Automatic Stabilizers for Aeroplanes, of whichthe following is a specification.

This invention relates to an automatic stabilizer for aeroplanes, andthe object is to provide means for controlling the devices by which thelateral control of the plane is effected.

vA further object is to provide automatic means for eli'ecting suchcontrol, and means for throwing out the automatic means when the pilotdesires to effect control' of the ailerons by hand.

A still further object ,is to provide means for controlling theelevators of the plane automatically and by hand.

-A still further object is to provide a particular form of governoracting in conjunction with air cylinders and plungers, and associatedelements. for effecting the movement of the controlling surfaces for thepurpose specied.

A still further object is to provide, in one form of the device, agovernor comprising a plurality of gyroscopes rotatable in a certainpredetermined relation hereinafter specified, in order that theresistance oilered by the gyroscopes with reference to an outside forcetending to alter the plane of rotation, will be manifest in a maximumdegree under practically all conditions.

A still further object is to provide particular means for controllingthe position of a plunger in an air cylinder by the relative movementtaking place between the elements of the stabilizing device and of theplane. a

With the foregoing and other objects in view, the invention consists inthe novel construction,y combination and arrangement of elementshereinafter described and claimed, it being understood that modicationsmay be made within the scope of the claims without departing from thespirit of the invention.

ln the drawings, Fi view of the stabilizer; igure-2 is a section on line2-2 of Figure 1; Figure 3 is a section on line 3-3 of Figure 1; Figure4' is an elevation looking from the right of Figre 1 is a top plan ure1; Figure 5 is a section on line 5--5 of Figure 1 (portions being inelevation in each sectional view) Figures 6 and 7 show the devicemounted on an airplane, and the resultsof inclination with reference tothe transverse axis of the machine; 4Figures 8 and 9 show how thecontrol is eected in `the eventof forward and downward inclination.(Figures 6 and 8 show the normal position, and Figures 7 and 9 thevariation therefrom.) A

In the practical embodiment of the invention, I provide .a plurality ofair cylinders 10 and 12, the plungers thereof being designed forconnection with certain elements specified below for producingrespectively the lateral control of 4the plane and the longitudinalcontrol thereof. The plunger within the cylinder 12 controls theelevators, and this cylinder may be of less diameter than the cylinder10, since less power is required for the longitudinal control. Thecylinders and the air connections thereof are identical in otherrespects, and proceeding to the description of cylinder 12, it should bestated that air enters this cylinder at the opposite end through theinletconnections 13 and 14, the air flowing from the tank 15, into whichair is forced by a pump 16 driven in any suitable manner, as by means ofone of the motors driving the propeller, or by means of an air screw.

Formed with the cylinder per se is an element 18 provided with a seriesof grooves or channels 19 constituting air ducts, the ports betweenthese ducts and the cylinder being equally spaced and being designated20. A plate 21 is bolted to the element 18, a suitable packing 22 beingprovided, and an air tight connection is thus effected.

The element 18 is provided with a circular opening 24 receiving atapered sleeve 25 in which the valve 26 operates. Ports 25 are 'formedin the element 25, and twov ports 26 are formed in the valve, and are sopositioned thatl two adjacent air passages and the ports' connectedtherewith f are opened at a given time. rThe plunger 28 in the cylinderl2 is of such proportions that the ports leading to the air passagesabove mentioned are covered two at a time, as the plunger'moves withinthe cylinder during the operation of the plane.

The outer end of the sleeve 25 is threaded externally and is engaged bythe internal threads of a cap 31, the latter also providing bearings ferthe stem 32 of the valvc Carried by the valve stem is a gear wheel 34meshing with a segment 35 referred to below. l f. 1

A kpiston rod 29 connected with the pis'- ton or plunger 28 carries atone end a forked element 37 which straddles a radial arm 38 serving topartly rotate or rock a shaft 39 mounted in bearings 39. vThis shaft isa tubular shaft and is adapted for connection by a clutch with theconcentric shaft 41 by means of which an arm or lever 42 is operated.This element last named serves to control the elevators by means of aconnecting rod 43 having a forked member 44 secured thereto landpivotally secured to the arm or lever 42. l

4TheO radial arm 38 carries a hub member 45 having one notch or recess46 for engagement by the single tooth 47 on the Aclutch collar 48slidable on the shaft 41, the shaft being provided with a spline 41acting to prevent the rotation of the collar. A hollow shaft 50 isprovided with a clutch element 51 having one or more notches 52 therein,with which the tooth 53 cooperates. A spring 54 serves to normally holdthe clutch collar 48 in engagement with the clutch element formed on thearm 38, in order that the movement of the element 38 will serve to rockthe shaft 41 and move the arm 42 thereby automaticallyr controlling theelevators.

The clutch element 48 is also under manual control through the medium ofconnecting wires or rods 55 operated by an angle lever 56 pivotallymounted at 57 and connected by means of a spring 58 and links of anysuitable character with a controlling angle member 59 pivotally mountedon the lever 60, this lever being of the type employed for the usualstick control. It has previously been stated that the clutch isnormally1 in position for permitting automatic control from the governoror gyroscope, but by the operation of the element 59 by the pilot, theclutch collar 48 is thrown into engagement with the clutch element 51,thereby releasing the arm 38 and throwing out the automatic control. Theshaft 50 may now be rocked by the stick or lever 60, resulting in thecorresponding movement of shaft 41 and of the lever 42 controlling theelevators, the tubular shaft 39 and radial arm 38 remaining unaffected.The socketed member 62 of the lever 60 has connected therewith, orformed thereon, a frame comprising a plurality of parallel elements" 63and 64, apertured centrally and receiving a pin 65 passing into a block66 rigid with reference to shaft 50', whereby the shaft is rocked uponthe movement of the lever 60 in a direction transversely of the shaft. Apin 68 on the frame just. referred to passes through the slotted portion69 of shaft 50, by means of which longitudinal control is "effected,through the ele,- vators.

The shaft 50. corresponds with the shaft 50 of the mechanism controllingthe ailerons, and the clutch element, and associated parts operate in asimilar manner, in each case.` In the mechanism controlling the aileronsthe radial arm 138 corresponds with the element 38, v)and is carried bya tubular shaft 139, and when the clutch element 148 is thrown in forautomatic operation, the shafts 139 and 141 rotate together, operatingthe lever 142 and controlling the ailerons.

A clutch collar 148 is controlled or operated by the angle member 159and angle member 156 connected therewith and with the collar 148. Theshafts 50 and 50 are at right angles lwith reference to each other, A

and the shaft 50 lincludes an offset member, forming a type of crank,slotted as described, the slot receiving pin 68. This constructionpermits the controlling lever or stick 60 to rock either shaft, theshafts being in the same plane, disregarding for the moment the offsetportion offthe shaft 50. When the shaft 50 is rocked, the pin 68 ofcourse moves within the slot without causing the rotation of the shaft50. The plunger 128 of Ithe cylinder 10 operates the piston rod 129, andis in connection with devices operating the ailerons. These devicesinclude an arm 160, shaftv 161, an arm 162, a rod 163, and an arm 138,this particular arrangement being employed if circumstances lrequire.Arm 138 operates or rocks hollow shaft`139, and the shaft 141, andthrows lever 142 connected with rods 164 leading to the aile ons.

Associated with the cylinder 1() is the valve 126, the stem of whichcarries rigidly a gear wheel( 134 meshing with a segment 135, and thesegments 35, and are in direct connection with the gyroscopic or other fform of governor.

The frame 75 of the gyroscope swings on trunnions 76, and the pivotedframe 77 carries a projecting element 78 movable inthe slot 75 of theframe 75. The axes about which the frames are tiltable, areperpendicular with reference to each other.

-The frame 77 includes a plurality of members 79 and 80 parallel witheach other, and connected with the circumferential portion of the frame7 7`in the manner shown. The

yelements 79 and 80 are provided with bear- The motors 87 and 88 forrotating the gyroscopes, receive current through wires 89 and 90,respectively, the wires passlng through the tubular axial members of theframe 81 and 82.

e oppositely located axial members 91 and 92 carry respectively gearwheels 93 and 94 of the same diameter and meshing with a central gearwheel 95 mounted for rotation about an axis coincident with the verticalaxis of the frame 77. This construction permits of the operationdescribed below.

A gyroscope arranged to rotate on a horizontal axis and supported in aframe rotatable on a vertical axis will oii'er more resistance to anoutside force te-ndin to force the gyroscope out of its original piane,than one mounted in a rigid frame. In so doing however it will impart arotary motion to the frame, such as thel frame 81 or 82, the directionof movement depending on the direction in which the gyroscope isrotating. rllhe gyroscope will also oii'er more resistt ance to theexterior force when the frame in which it is mounted is rotating on itsvertical axis freely, but a force brought to bear on a gyroseope somounted, in the plane in which it is rotating will not be resisted bythe gyroscope, although a force brought to bear in a plane at a rightangle, or at any other angle, to the plane in which the gyroscope isrotated will be resisted, and a rotary motion will be imparted to theframe in which it is mounted. It will be seen therefore that since inthe present case the gyroscopes are mounted in frames at right angles toeach other, one of them will always be in position to resst a forcebrought to bear on the frame 77, from any angle. But in resisting thisforce, the frame supporting the gyroscope which is in position to o'l'erthe most resistance to the exterior force, will rotate on its verticalaxis, and the gyroscope will be turned into such a position as to otferno resistance to the eX- terior force. The movement of the framesupporting the gyroscope will however be communicated through thegearing referred to and including elements 93, 94 and 95, to the framesupporting the other gyroscope, turning it in the same degree, orthrough the same angle and placing said gyroscope in va osition to resstthe external force. Thereore one of the gvroscopes will always be in aposition to resist a force brought to bear on the mechansm and tendingto force it from its original position. In many instances, bothgyroscopes will be in a position to resist the applied force, or theywill alternate in rapid succession in resisting that force. Thegyroscopes of course rotate in the same direction, either clockwise orin the reverse direction, because if they rotate reversely withreference to each other they will neutralize each other, and fail to Therudder bar In the diagrammatic view the ailerons are K designated 8l andthe elevators are shown at 82.

When the air craft is thrown out of the plane representing itsstabilized position, this plane bein" at a right angle with reference tothe plane of the gyroscopc governor, the governor tends to maintain itsoriginal plane, with reference to the air craft. This causes one frameor the other of the gyroscopes, dependin upon whether the changeof planeis in a ateral or longitudinal direction, to' move in harmony with thegovernor, transmitting an equal movement to p'nion 93 or 94 and thenceto valve 26 or valve 126 causing the valve thus operated to registerwith the ports illustrated in Figure 5, the movement being to the rightor to the left of the central position, depending upon the direction ofchange of plane. As these ports are opened, the air pressure on the sideof the piston or plunger affected is reduced by the air escaping throughthese ports. The inlet ports for the cylinders 10 and l2 are smallerthan the outlet ports, permitting the air to escape faster than thepressure is renewed or built up from the air tank. The piston thus movesto the side of reduced pressure until it covers two adjacent ports,closing them and preventing ifurther escape of air, thus causing thepressure to be agalin equalizcd by the How of air from the tan Theconnections between the plungers and the stabilizing surfaces are suchthat the surfaces are moved upwardly or downwardly in such degree as tocorrect the p0- sition of the air craft which caused the movement of thegovernor in relation to the plane of the craft and whch set in. motionthe stabilizing mechanism. I

As the air craft returns to stabilized position, the governor also movesback to its original position, with reference to the air craft, causinga reverse movement in the stabilizing mechanism, the valve 26 or valve126 moving back to its central position and opening the ports on theother side of the piston for reducing the pressure on that side, andcausing the piston to move in that direction until it covers the openedorts.

y This movement, as before, is communicated to the stabilizing surfaces,so that as the air craft returns to a stabilized position these surfacesreturn to their central position. The stabilizing surfaces are thereforealways in a position to correct the plane of the air craft at thatparticular moment, and as the craft moves back to its correct position,the stabilizing surfaces are moved accordingly.

What is claimed:

1. In mechanism of the class described, a lever, ailerons andcontrolling means therefor operable upon the manual operation of thelever, elevators and controlling means therefor operable upon the manualoperation of the lever in another direction, and automaticmeanssgovcrning the operation of the controlling means for the aileronsand elevators, said automatic means including cylinders perpendicular toeach other, valves having their axes perpendicular to the respectivecylinders, gyroscopes, and means for controlling the valves from thegyroscopes.

2. In mechanism of the class described, a lever, ailerons andcontrolling means therefor operable upon the manual operation of thelever, elevators and controlling means therefor, operable upon themanual operation of the lever in another direction, and automatic meansgoverning the operation of the controlling means for the ailerons andelevators, said automatic means including cylinders perpendicular toeach other, valves having their aXes of rotation perpendicular to therespective cylinders, gyroscopes and means for maintaining their axes ofrotation perpendicular to each other, and means for controlling thevalves from the gyroscopes.

3. In mechanism of the class described, a shaft, means controlling anelevator or the like by the rotation of the shaft, spaced engagingelements loosely mounted on said shaft, one of the engaging elementsbeing automatically controlled and the other being controlled manually,and a third engaging element through which rotation may be imparted tothe shaft when this engaging n element co-acts with either of theengaging elements first named.

4r. In mechanism of the class described, a shaft, means controlling anelevator or the like by the rotation of the shaft, spaced engagingelements loosely mounted on the shaft, one ofthe engaging elements beingautomatically controlled and the other being controlled manually, and athird engaging element through which rotation may be imparted to theshaft when this engaging element co-acts with either of the engagingelements first named, tubular elements mountin two of the engagingelements, the thir engaging element being longitudinally movable in twodirections, between the engaging elements first named.

5. In mechanism of the class described, a lever, stabilizing surfaces,an air cylinder and a plunger therein, a governor including a gyroscope,a housin providing a valve chamber, a valve control ing the admission ofair to the cylinder for operating the plunger upon a relative change inposition between the cylinder and the gyroscope, a shaft, connectionsbetween the lever and the shaft, permitting the latter to be rockedmanually upon the movement of the lever, means for effecting theautomatic control of the shaft through the medium of the governor, saidhousing having air ducts entering tbe cylinder along a longitudinal lineand entering the valve chamber in circumferential series, and means forshifting thev stabilizingsurfaces upon the movement of the shaft.

6. In mechanism of the class described, a lever, stabilizing surfaces,an air cylinder and a plunger therein, a governor including a gyroscope,a housing providing a valve chamber, a valve controlling the admissionof air to the cylinder for operating the plunger' upon a relative changein position between the cylinder and the gyroscope, a shaft, connectionsbetween the lever and the shaft, permitting the latter to be rockedmanually upon the movement of the lever, means for efectin the automaticcontrol of the shaft throug the medium of the governor, said housinghaving air ducts entering the cylinder along a longitudinal line andentering the valve chamber in circumferential series, means for shiftingthe stabilizing surfaces upon the movement of the shaft, and means forthrowing out the automatic controlling means.

7. In mechanism of the class described, a plurality of shafts at anangle with each other, means connected with the shafts for controllingrespectively the movement of an air craft about its longitudinal axisand its transverse axis, a lever manually operable for rocking eithershaft, a governor and means connected therewith for controlling eithershaft automatically, and means associated with the lever for throwingout the automatic control and simultaneously placing either shaft undermanual control.

8. In mechanism of the class described, a plurality of shafts at anangle with each other, means connected with the shafts for controllingrespectively the movement of an air craft about its longitudinal axisand its transverse axis, a lever manually operable for rocking eithershaft, a governor and means connected therewith for controlling eithershaft automatically, and means associated with the lever for throwingout the automatic control and simultaneously placing either shaft lundermanual control, said lever being mounted on one of the shafts and beingmovable in one direction for rocking that shaft, and means including aslotted crank on the other shaft, causing the shaft last named to beindependently rocked upon the movement of the lever in anotherdirection.

9. In mechanism of the class described, a plurality of shafts at anangle with each other one of the shafts including a slotted crankportion, means connected with these shafts for controlling respectivelythe movement of an air craft about axes perpendicular to each other, alever for manually rocking either shaft the lever passing through theslotted crank portion, a governor and fluid pressure means connectedtherewith for controlling either shaft automatically, and meansassociated with the lever for throwing out the automatic control ofeither shaft and simultaneously placing said shaft under manual control.

10. In mechanism of the class described, a gyroscopic governor includinga plurality of frames pivoted for movement about axes perpendicular toeach other, a plurality of air cylinders and plungers therein, means foradmitting air to the cylinders on opposite sides of the plungers, meanspermitting the reduction of air pressure on one side of a given plungerupon relative movement between the elements of the governor and the axisof an aircraft, said means including valve housings having radial ports,the cylinders having ports in longitudinal series and in communicationwith the ports of the housings, valves within the housings and havingports registering with some of the ports of said housings, stabilizingsurfaces, and connections between said surfaces and lthe plungers.

11. In mechanism of the class described, a roscopic governor including aplurality ofgfiames ivoted for movement about axes perpendicular to eachother, a plurality of air cylinders and plungers therein, means foradmitting air to the cylinders on opposite sides of the plungers, andmeans permittin the reduction `of the air pressure on one'si e of agiven plunger, at a given time, upon`relative movement between thegovernor and an axis of an air craft, said means including valvehousings having radial ports, the cylinders having ports in longitudinalseries and in communication with the ports of the housings, valveswithin the housings and having ports re istering with some of the portsof said ousings, the degree of pressure reduction being determined bythe extent of relative movement specified, stabilizing surfaces andconnections between sald surfaces and the plungers.

12. In mechanism of the class described, a frame, stationary mountingmeans whereby the frame is supported for pivotal movement, a pluralityof frames pivote'd on vertical axes in the frame first named, agyroscope mounted on a horizontal axis in each of the frames last named,the axes of the gyroscopesv being perpendicular to` each other,intermeshing devices for maintaining perpendicular relation, a slottedsegmental frame in the -plane of the frame iirst named, means on theframe rst named engaging the slotted portion, stabilizing surfaces, andmeans controlling the latter by relative movement 'between the mountingmeans and the gyroscope.

13. In mechanism of the class described, a frame, stationary mountingmeans whereby the frame is supported for pivotal movement, a pluralityof frames pivoted on vertical axes in the frame first named, a gyroscopemounted on a horizontal axis in each of the frames last named, the axesof the gyroscopes being perpendicular to each other, intermeshingdevices for maintaining perpendicular relation, a slotted segmentalframe in the plane of the frame first named, means on the frame lirstnamed engaging the slotted portion, stabilizin surfaces, and fluidpressure means control ing the stabilizing surfaces by relative movementbetween the mounting means and the gyroscope, said fluid pressure meansincluding valves rotatable on axes perpendicular to cach other andhaving radial ports in circumferential series controlled by theaforesaid relative movement between the mounting means and gyroscope,the slotted` frame controlling the valves. In testimony whereof I alix msi nature.

HARRY A. E RIE.

